Megabonk Bloodmark: Fastest Unlock Route and Effects That Supercharge Your Build

File this under: the game absolutely does not tell you this, but it changes everything. Megabonk has a status effect called Bloodmark that quietly turns tough runs into target practice. It is not explained in-game, it is weirdly powerful, and yes, you can start using it basically right away. Here is the straight-line version of how to get it and what it actually does.

How to get Bloodmark (and what the game forgets to mention)

Bloodmark is not a standalone unlock or a menu toggle. It comes from a specific item: Unstable Transfusion. That item is available from the start, and its description is the only place the game really hints at what is going on:

"+27% chance to apply a stack of Bloodmark when hitting an enemy"

Items appear at random, so you might not see Unstable Transfusion on your first run. When it does show up, do not overthink it — grab it. Each copy you pick up makes Bloodmark hit harder and stack higher, which is exactly why this thing is so good on higher difficulties.

What Bloodmark actually does

When a Bloodmark stack lands on an enemy, it carves out a chunk of their effective health and draws a purple threshold on their HP bar. Drop their current HP to that purple line and you can execute them on the spot. That instant-finish works on regular enemies and on bosses, which is why runs start to feel like you turned the difficulty down once Bloodmark is rolling.

Because the effect scales by percentage, it is even better against chunky health pools. A single 27% chance might sound low, but if you are landing lots of hits, stacks add up fast — and once that purple threshold appears, the fight is basically over.

Quick hits

• Unstable Transfusion is in the item pool from the jump; you do not need to unlock it via progression, you just need to find it during a run.
• More copies of Unstable Transfusion = bigger Bloodmark impact and more consistent application across all enemy types.
• Bloodmark works on every enemy, including bosses. If their HP dips to the purple line, you can execute immediately.
• It is an all-character, high-damage build staple. It slots into basically any kit.
• Want extra reliability? Pair it with the Overpowered Lamp, which reads "+1 chance to proc on hit effects". More procs means more Bloodmark stacks.
• The 27% application chance is per hit. Attack fast and it stops feeling like 27% very quickly.
• Megabonk details: developed by vedinad, released September 18, 2025, on PC and Linux.

Bottom line

If Unstable Transfusion shows up, you take it — and if it shows up again, you take it again. Bloodmark turns big, annoying health pools into a purple finish line, and once you start playing around that line, bosses go down way earlier than they should. Feels a little like cheating. Works like a dream.